Direct bonding is a method in which a display screen and a touch screen are fully bonded together with no gap using an optical clear resin (OCR) or an optical clear adhesive (OCA). As compared with air bonding, the direct bonding technique eliminates air between the screens, and this helps reduce light reflection between the display panel and glass. As a result, the screen appears to be more transparent and the display effect of the screen may be improved.
However, due to inconsistency of reinforcing degrees of both sides of reinforcing glass for the touch screen, there is a stress difference between the both sides, thereby resulting in warping of the glass, and especially an OGS (one glass solution) touch screen is liable to be warped. For the direct bonding of the OGS touch screen and the display screen, there will be a risk that the peeling force of the adhesive is insufficient and the adhesive may fail.